A variety of new NMR methods will be developed for the purpose of enhancing structural studies of biologically important molecules, in the solution and solid state. Selective cross-relaxation pulse sequences will be developed in order to enhance the specificity of the nuclear Overhauser effect in solution state biomolecules. The aim is to improve the quality and reliability of NMR-determined structures in solids. Frequency-switching pulse sequences will be developed for applications in solid state NMR. We expect to achieve low-power dipolar decoupling, particularly important for studies of temperature-sensitive biological materials. Rotational resonance in solids hold great promise for deriving specific structural information from molecules too large to provide useable solution spectra. New theoretical and numerical techniques will be employed to understand existing results and to develop new experimental schemes with an easier quantitative interpretation.